Protection devices of this type are already known which comprise coverings made up of numerous parts that the operative must assemble on the site where the cable is being installed. The parts comprise copper or lead tubes that the operative must weld or screw together, rings of brass, bronze, or insulating material, gaskets that may be toroidal or flat, boxes made of fiberglass reinforced epoxy resin, connection equipment, fasteners, heat-shrink sheaths, mastic, and a large quantity of filler for casting on site.
Such coverings are expensive, difficult to assemble, and the extent to which they are leakproof depends mainly on the skill of the operative.